jch+@cs.cmu.edu (Jonathan Hardwick) (06/19/91)
Question for the net: A housemate has an original Big Blue IBM PC, running at the blazing speed of 4.77MHz. We want to use this as a dumb terminal to access our university workstations. The university offers 2400 bps service with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV modems. We'd really like the extra speed if possible. Is the PC going to be able to keep up with 19200 bps? How about 9600 bps? It must be at least 5 years since I touched a PC, so I've lost any idea I may once have had for the speed of these beasts... Oh, and if the PC *can't* keep up, what sort of motherboard upgrade would we need? 10 MHz 8086? 80286? Thanks for any information, Jonathan Hardwick, School Of Computer Science, Carnegie Mellon Univ.
tau-ceti (06/19/91)
jch+@cs.cmu.edu (Jonathan Hardwick) writes: > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? I think not. And, if my aged, infirm memory is correct, it isn't the motherboard's fault. It's the inherent capability of the chip onboard your comm port. You need a 16 bit card to accomplish this speed. How about 9600 bps? Yes, I believe, given the right card, you can do 9600 ok, though. > > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? Given the fact that a 286 12 mz motherboard for a PC runs less than 150 dollars these days, depending upon how robust you will need it to be, I think you should upgrade, anyway. Just make certain it will fit the OEM IMB case. Some will, some won't. > > Thanks for any information, > Jonathan Hardwick, School Of Computer Science, Carnegie Mellon Univ. --------------------------------------------------------------------------- dave@kharma (Dave Laird) | (___) | The Computer Concern, Springdale SYSOP: Used Kharma Lot BBS | (O O) | Washington 509-233-8474 *HST* _____________________________| (._.) |___________________________________ ++ isc-br!tau-ceti!dogear!kharma!dave ++
tnixon@hayes.uucp (06/19/91)
In article <1991Jun18.201125.6198@cs.cmu.edu>, jch+@cs.cmu.edu (Jonathan Hardwick) writes: > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? Before coming to Hayes, I worked for Datamaxx USA Corp, writing firmware for terminal emulators. Their biggest-selling product was based on a Motorola 6800 processor running at 1 MHz, and supported up to 9600bps -- without flow control, and without ever losing data! So, I _know_ that a 4.77MHz processor _can_ support 9600, even 19200, _if_ your comm software is well written. That's the real trick: finding a program that is efficiently written, properly supports flow control, scrolls fast, properly schedules writes to disk to avoid slowdowns, etc. Hayes Smartcom Exec is one such program (its what I use), but I'm sure you can get plenty of recommendations for good programs that can keep up with 9600 or 19200 on a 4.77 MHz PC. If you're doing anything fancy on the PC (running TSRs that hook into the timer interrupt, or a LAN card, or RAMdisk), then you may want to invest in a buffered serial port card like Hayes ESP. This provides 1024 bytes of buffer in the hardware, plus automatic hardware flow control, so even if the main CPU gets a bit behind tending to other things, you still don't lose characters. It's a lot cheaper and easier than getting a new motherboard, assuming you're using a modem that has flow control. So, anyway, my advice is, "go for it". -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net
ted@isgtec.uucp (Ted Richards) (06/19/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > Question for the net: > > A housemate has an original Big Blue IBM PC, running at the blazing > speed of 4.77MHz. We want to use this as a dumb terminal to access > our university workstations. The university offers 2400 bps service > with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV > modems. We'd really like the extra speed if possible. Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? I have some bad news for you. I have one of these geriatric beasts, too, and it doesn't even come close to keeping up at 9600 baud. The problem is in the screen updates, not the comms port, which manages file transfers at almost full speed (~ 860-920 cps). The speed varies depending on the comms programm. I have tried Procomm, Telix and two varieties of MS_kermit. Telix is really awful (unfortunate, because I like the programm a lot). Even with Telix doing its own screen updates (the fastest mode), it fills the screen at perhaps 300 cps when scrolling, somewhat better when clearing the screen first. The latest Kermit is not much better. Procomm was, I think, a little faster, but I tried it a year ago, so I don't remember exactly. The best performance, perhaps 500-600 cps, comes from a very old copy of Kermit, dated 1982 or 1983 that I found lying around on an old diskette. Perhaps someone else has found another comms program that can keep up? By the way, I am using a Telbit T1000 on my end, talking to a T2500 (at 9600 baud) at work. > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? Can't help you here, since I haven't done anything about it (I'm saving up for a 386-25, myself). -- Ted Richards ...uunet!utai!lsuc!isgtec!ted ted@isgtec.UUCP ISG Technologies Inc. 3030 Orlando Dr. Mississauga Ont. Canada L4V 1S8
mcdonald@aries.scs.uiuc.edu (Doug McDonald) (06/20/91)
In article <1155@isgtec.UUCP> ted@isgtec.uucp (Ted Richards) writes: >In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: >> Question for the net: >> >> A housemate has an original Big Blue IBM PC, running at the blazing >> speed of 4.77MHz. We want to use this as a dumb terminal to access >> our university workstations. The university offers 2400 bps service >> with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >> modems. We'd really like the extra speed if possible. Is the PC >> going to be able to keep up with 19200 bps? How about 9600 bps? > >I have some bad news for you. I have one of these geriatric beasts, >too, and it doesn't even come close to keeping up at 9600 baud. The >problem is in the screen updates, not the comms port, which manages file >transfers at almost full speed (~ 860-920 cps). > >The speed varies depending on the comms programm. I have tried Procomm, >Telix and two varieties of MS_kermit. Telix is really awful >(unfortunate, because I like the programm a lot). Even with Telix doing >its own screen updates (the fastest mode), it fills the screen at >perhaps 300 cps when scrolling, somewhat better when clearing the screen >first. The latest Kermit is not much better. Procomm was, I think, a >little faster, but I tried it a year ago, so I don't remember exactly. > >The best performance, perhaps 500-600 cps, comes from a very old copy of >Kermit, dated 1982 or 1983 that I found lying around on an old diskette. > >Perhaps someone else has found another comms program that can keep up? > >By the way, I am using a Telbit T1000 on my end, talking to a T2500 (at >9600 baud) at work. > >> Oh, and if the PC *can't* keep up, what sort of motherboard upgrade >> would we need? 10 MHz 8086? 80286? > >Can't help you here, since I haven't done anything about it (I'm saving >up for a 386-25, myself). > >-- A plain PC at 4.77 MHz can EASILY keep up with 19200 baud including output to the screen. You just have to have an EGA card or higher (or maybe a CGA or mono, I've never tried). You do it by scrolling NOT by actually moving characters around in video memory, but by setting up a double-length video buffer (twice the length of the screen) and keeping TWO copies of your text in it in double-circular-buffer mode. You then just move the start-of-memory pointer on the video card to scroll. And, amazingly enough, on my 386 this works fine up to 9600 baud **in graphics mode**!!!! Doug McDonald
pshuang@athena.mit.edu (Ping-Shun Huang) (06/20/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > We'd really like the extra speed if possible. Is the PC going to be > able to keep up with 19200 bps? How about 9600 bps? I think the original IBM-PC would be hard pressed to keep up with even 9,600 baud modems, much less a 19,200 connection. It may be just barely possible for this to work if you have (a) a communication program which doesn't impose too much overhead -- obviously comm programs which run under Windows are out, but character-based comm programs vary widely in the CPU time they "waste" in doing other processing; I would try {commo}, which is a very un-memory-intensive, un-CPU-intensive shareware comm program; (b) a serial port which knows how to buffer incoming characters (FIFO = First In, First Out). There's a serial port chip called 16xxxA, which can buffer a few characters. I don't know the details about the new Hayes smart serial ports, but they almost certainly also implement buffering, too. If you want to upgrade to better CPU, I would imagine a 12Mhz 80286 should do the job... probably better if you still consider (a) & (b). -- Above text where applicable is (c) Copyleft 1991, all rights deserved by: UNIX:/etc/ping instantiated (Ping Huang) [INTERNET: pshuang@athena.mit.edu]
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (06/20/91)
>> A housemate has an original Big Blue IBM PC, running at the blazing >> speed of 4.77MHz. We want to use this as a dumb terminal to access >> our university workstations. The university offers 2400 bps service >> with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >> modems. We'd really like the extra speed if possible. Is the PC >> going to be able to keep up with 19200 bps? How about 9600 bps? >I have some bad news for you. I have one of these geriatric beasts, >too, and it doesn't even come close to keeping up at 9600 baud. The >problem is in the screen updates, not the comms port, which manages file >transfers at almost full speed (~ 860-920 cps). Hmmmm... I am at this moment using a Leading Edge model D with a direct serial line running at 9600 baud, with a Sytek box at the other end and I don't have any trouble when the switch on the back is set at 4.77 MHz. If your screen scrolls too slowly, try running something like FansiConsole to speed it up (I do). -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS ! -------------------------------------------------------------------------------
curt@cynic.wimsey.bc.ca (Curt Sampson) (06/20/91)
In article <1991Jun18.201125.6198@cs.cmu.edu> jch+@cs.cmu.edu (Jonathan Hardwick) writes: > Is the PC > going to be able to keep up with 19200 bps? How about 9600 bps? > > Oh, and if the PC *can't* keep up, what sort of motherboard upgrade > would we need? 10 MHz 8086? 80286? I've got a similar question, actually. I'm runing SCO Xenix 2.3.2 on a 12 MHz 80286. When testing with a V.32 modem and the FAS driver (using a 16550 with the buffer turned on) I'm only getting about 450 cps. Things seem to be configured correctly, so I'm at a loss to see what could be causing this. Could it be that my CPU just doesn't have enough oomph to work faster? I'd appreciate any comments or experiences that anyone can share. cjs -- | "I suspect the principle difference between us is | that I spend a lot of time walking around the tree | trying to find the best way to shake it while you Curt Sampson | are more concerned with whether an axe or a chain-
caf@omen.COM (Chuck Forsberg WA7KGX) (06/20/91)
A 4.77 MHz PC can keep up with a 9600 bps modem. A 16550A/AFN UART chip helps; you'll need it to make up for newer versions of DOS. A CGA slows things down. Use an MDA, EGA or VGA for more speed. Unfortunately, upgrading the display may cost more than the PC is worth. Most programs scroll by copying memory. The alternate approach (of necessity on 6800 systems) does not work well when scrolling regions are set. I would suggest downloading a copy of ZCOMM from TeleGodzilla or a local BBS. It is about as quick as they come unless tested by PC Magazine "experts". If the computer has a CGA try setting ZCOMM's "display warpdrive" to speed things up. Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ Omen Technology Inc "The High Reliability Software" 17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406 TeleGodzilla:621-3746 FAX:621-3735 CIS:70007,2304 Genie:CAF -- Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ Omen Technology Inc "The High Reliability Software" 17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406
U39648@uicvm.uic.edu (From The Mind Of) (06/20/91)
>A housemate has an original Big Blue IBM PC, running at the blazing >speed of 4.77MHz. We want to use this as a dumb terminal to access >our university workstations. The university offers 2400 bps service >with MNP level 5, and a 9600 bps or 19200 bps MCN service using DOV >modems. We'd really like the extra speed if possible. Is the PC >going to be able to keep up with 19200 bps? How about 9600 bps? It >must be at least 5 years since I touched a PC, so I've lost any idea I >may once have had for the speed of these beasts... > >Oh, and if the PC *can't* keep up, what sort of motherboard upgrade >would we need? 10 MHz 8086? 80286? Your PC should be able to keep up if you replace the UART that controls your serial port. It's probably an 8250, so you can replace it with a NS16550A directly, which has a FIFO buffer to help handle high speed transfers, especially on slower machines or fast machines running multiple tasks. This chip is inexpensive, and you should be able to get one for under $20. - Darius ========================================================================= BITNET: U39648@UICVM | "I'd rather laugh with the sinners Internet: u39648@uicvm.uic.edu | than cry with the saints, ====================================| the sinners are much more fun, "Don't set fire to strangers." | and only the good die young." - Mr. Zarniwoop | - Billy Joel
root@zswamp.uucp (Geoffrey Welsh) (06/21/91)
In a letter to All, Jonathan Hardwick (jch+@cs.cmu.edu ) wrote: >A housemate has an original Big Blue IBM PC, running at the >blazing >speed of 4.77MHz. We want to use this as a dumb terminal to >access >our university workstations. The university offers 2400 bps >service >with MNP level 5, and a 9600 bps or 19200 bps MCN service >using DOV >modems. We'd really like the extra speed if possible. Is >the PC >going to be able to keep up with 19200 bps? How about 9600 >bps? Question: Will a 4.77 MHz 8088 do 19,200 (9600) bps? Answer: 9600 probably, 19200 probably not. However, install an NS16550AFN chip in place of the 8250 or 16450 chip on your serial port (and use software which supports it), and the problem's solved. Comment: The only DOV (data over voice) modems I know of are devices which can transmit data, modulated at high frequencies, over existing direct wires. These are useful where a telephone system (e.g. PBX) is already installed and you want to put terminals on people's desks without rewiring the world. They don't work over dialup lines. >Oh, and if the PC *can't* keep up, what sort of motherboard >upgrade would we need? 10 MHz 8086? 80286? There are a *lot* of variables involved. The best (and cheapest) solution is the 16550. -- Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root 602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 "He who claims to know everything can't possibly know much" -me
wb8foz@mthvax.cs.miami.edu (David Lesher) (06/21/91)
It's important to define what you mean by "keep up" in this case.
Case in point: Several years back, I was flogging a wideband WAN system
to get some idea how well it might handle some big graphics dumps.
I used both 11/34's and that new-fangled 11-750 {I said it was a few
years ago, remember?} to spit out characters as fast as possible. For
destinations, I used a variety of terminals {i.e. whatever I could
snitch from folk's offices when they went to meetings;-} such as those
somewhat weird-looking HP things, VT-100's, AJ's, etc.
Not a one could keep up @ 19,200. They just could not write fast
enough. They would X-off back, catch a breath, and start again just
fine, but without flow control, forget it. Now since nobody could read
that fast, that's no problem. But I did have limited access to two 19"
Tek graphics boxes with price tags to match. They did keep up. Maybe
the 80286 aux-processors helped ;-}
On a PeaSea, I suspect the video would be the biggest drain. Stick to
a mono text card, if you can FIND one, and I bet it will work, with
flow control, of course.
BTW, if I fed all 8 ports on the Sytek/Localnet box @ 19,200, its z-80
got very confused, and crashed every time. Wonder why;-?
--
A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu
& no one will talk to a host that's close............(305) 255-RTFM
Unless the host (that isn't close)......................pob 570-335
is busy, hung or dead....................................33257-0335root@zswamp.uucp (Geoffrey Welsh) (06/22/91)
>From: tnixon@hayes.uucp >Before coming to Hayes, I worked for Datamaxx USA Corp, >writing firmware for terminal emulators. Their biggest- >selling product was based on a Motorola 6800 processor >running at 1 MHz, and supported up to 9600bps -- without >flow control, and without ever losing data! So, I _know_ >that a 4.77MHz processor _can_ support 9600, even 19200, >_if_ your comm software is well written. There's more to it than that. (My qualifications: I wrote a 9600 bps serial driver for a 2 MHz 6502 system, *without* a UART. Yup, we're bit-banging 9600 while scrolling an 80*25 16-colour screen, and not losing a single character!) The 6800 (and the 6502) have fast interrupt response times. Since the longest instructions are only a few cycles long (7 on the 6502!), the interrupt is recognized quickly; on an 8088, I believe that it must wait for the current instruction to finish (meaning up to 200 clock cycles!). The CPU's instruction pointer is only 16 bits, and the flags only 8 bits, meaning that only three bytes absolutely need be stacked before the interrupt service routine is called; on an 8088, those numbers are doubled. On a 6502, an 8 bit push instruction takes two clock cycles (arguably one for the instruction fetch, the other for the register write); on an 8088, a memory access is four clock cycles (lending credence to the old saying that a 4.77 MHz XT isn't any faster on byte shuffling than a 1.02 MHz 6502 a la PET or Apple ][). If the interrupt routine decides to stack the enture CPU state, the 6502 has only a couple registers to push, while the 8088 has several. The bottom line is that a 1 MHz 6800 can probably react to an interrupt request and begin useful processing in less than 20 microseconds. A 4.77 MHz XT, however, may require 60! In terms of raw performance, the 8088 may be more powerful than the 6800, but it is mush slower at shuffling bytes. You're not likely to need longword division in an interrupt service routine, so the bigger processor is at a disadvantage... on the other hand, the long instructions are more likely to show up in the application being interrupted, so the bigger processor is again at a disadvantage. >That's the real trick: finding a program that is efficiently >written, properly supports flow control, scrolls fast, properly >schedules writes to disk to avoid slowdowns, etc. Hayes >Smartcom Exec is one such program (its what I use), but I'm sure >you can get plenty of recommendations for good programs that can >keep up with 9600 or 19200 on a 4.77 MHz PC. With a UART, 9600 bps on a 4.77 MHz XT should not be a problem unless you're throwing something really nasty at it (like multitasking, Perstor ARLL controllers, or truly shabby code). 19200 usually causes trouble. On 286 ATs, accessing extended memory from DOS (i.e. taking the processor from protected to real mode) is also a source of trouble. >So, anyway, my advice is, "go for it". Never hurts. If it works, don't fix it! If not, the 16550 is an easy solution (assuming that your software supports it). -- Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root 602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 "He who claims to know everything can't possibly know much" -me
keating@motcid.UUCP (Edward Keating) (06/24/91)
In article <243.2861EA82@zswamp.uucp>, root@zswamp.uucp (Geoffrey Welsh) writes: > In a letter to All, Jonathan Hardwick (jch+@cs.cmu.edu ) wrote: > > >A housemate has an original Big Blue IBM PC, running at the > >blazing > >speed of 4.77MHz. We want to use this as a dumb terminal to > > Question: Will a 4.77 MHz 8088 do 19,200 (9600) bps? > > Answer: 9600 probably, 19200 probably not. However, install an NS16550AFN > chip in place of the 8250 or 16450 chip on your serial port (and use software > which supports it), and the problem's solved. The answer to the question of whether or not a 4.77Mhz 8088 can do 19,200 is YES. Most laplink (or clones) programs run the comm port at 115Kbps which is in excess of 11k cps. My original PC-1 regularly performs this feat with an 8250 that has never been touched. The question that you should ask was, is there a modem program fast enough to display information at 9600bps. Most communication programs are limited by the display hardware involved and by the capability of the operator to read the information that scrolls by. (You need a super fast reading course to keep up at the >9000 words/minute rate.) If all comes down to time. At 1920 cps you receive characters every 520 microseconds. If the communication program attempts to display every character as it is received, then you will fall behind. To keep up with the comm link, the communication program will have to buffer characters from the link and display them as a string. This leads to a display that is hard to read. (It becomes a very "jerky" display). Displaying characters as they are received has a smoothing effect so that it becomes more readable. Dec Vt100s with "smooth scrolling" enabled do not display more than 120cps effective rate. They control the host with an excessive amount of XON/XOFF characters. If you are evaluating communication programs, Procomm 2.4 will keep up with the comm link at 240 - 480 cps. Procomm Plus will display 2-3 times faster (again, your mileage may vary depending on your display adapter. CGA is worst, MDA with the long persistence monitor is better, and EGA/VGA are usually faster. Check out the PC Mag reviews for the fastest display times of cards for the mode you wish to operate in, text/graphics and pick a card.)
robertsw@gtephx.UUCP (Wild Rider) (06/25/91)
In article <1991Jun20.125829.15405@omen.COM> caf@omen.COM (Chuck Forsberg WA7KGX) writes: >A 4.77 MHz PC can keep up with a 9600 bps modem. as part of a project i was involved in, i wrote a vt100 comm program with the requirement that it had to keep up with a dec vt100 terminal at 9600 bps, even when running on a 4.77mhz pc. it did, but just barely. the comm program (called pc100) was (is) written entirely in c, yes, even the comm port isr. ("assembly? we don't need no steenkin' assembly!" :-) the default receive buffer was 2k, which created an "interesting" delay when you pressed ctrl-s to suspend. :-) actually, with proper handshaking & buffering, even a plain old pc should be able to just keep it's head above water at 19.2kbps. don't expect any background/foreground stuff, though! :-) >-- >Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf >Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ > Omen Technology Inc "The High Reliability Software" >17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406 i suppose in the presence of a wizard like chuck forsberg, any pc would perform well, even at 9600 bps. :-) cheers, wr (the wild rider) -- Wallace Roberts, AG (formerly GTE) Communication Systems, Phoenix, AZ UUCP: ...!{ncar!noao!asuvax | uunet!zardoz!hrc | att}!gtephx!robertsw Internet: gtephx!robertsw@asuvax.eas.asu.edu Bike: '82 GS1100L Suz voice: (602)581-4555 fax: (602)582-7624 Cage: '89 Mustang GT
johnk@gordian.com (John Kalucki) (06/25/91)
What about faster data rates on PCs in general. How fast can I drive a PC's async port, running PCRoute for example, and still have it keep up? Are there special purpose PC boards that will allow say 56kbit connections? -John Kalucki johnk@gordian.com
skipm@dorsai.com (Dorsai SysOp) (06/25/91)
dogear!kharma!dave@isc-br!tau-ceti writes: > Given the fact that a 286 12 mz motherboard for a PC runs less than 150 > dollars these days, depending upon how robust you will need it to be, I think > you should upgrade, anyway. Just make certain it will fit the OEM IMB case. > Some will, some won't. > Some manufacturers make some really small mini-AT's that are square in size, and fit in the space of about 1/3 a full-sized AT board. I've mounted these in original IBM PC cases, and with a little work figuring out where you should put standoffs, they're fine. Be care with what model you select - make sure the RAM, if it's the SIMM or SIP type is not near the drive cages - you'll have a hard time fitting the board in if you can at all. Be sure too to place electrical tape or some sort of insulating material on the border edges of the case where the original PC motherboard sat, otherwise you'll short the whole shebang out. Skip ************************************************************************** ** SkipM@DORSAI.com - The Dorsai Embassy / Dorsai Diplomatic Mission ** ** (Systems Manager) - Consulate : (212) 431-1944 ** ************************************************************************** ** "The difference between a good man, and a bad man, is the choice of ** ** cause." - Unknown ** **************************************************************************
marc@aria.ascend.com (Marco S Hyman) (06/25/91)
In article <7382@bone34.UUCP> keating@motcid.UUCP (Edward Keating) writes: > If you are evaluating communication programs, Procomm 2.4 will keep up > with the comm link at 240 - 480 cps. Procomm Plus will display 2-3 > times faster (again, your mileage may vary depending on your display > adapter. CGA is worst, MDA with the long persistence monitor is better, > and EGA/VGA are usually faster. Check out the PC Mag reviews for the > fastest display times of cards for the mode you wish to operate in, > text/graphics and pick a card.) Procomm Plus will not keep up with a full duplex ascii transfer at 19.2 Kbps. A full duplex ascii transfer is _the_ comm program torture test. The best I've found (in spite of its user interface which I hate!) is Hayes Smartcom III. It will handle 19.2 Kbps full duplex ascii transfers on two serial ports simultaneously. This is a good thing when you're using PCs and comm programs as lab test equipment. (I remember once spending hours looking for a bug in a serial driver because a PC comm program was dropping characters. Now I get a protocol analyzer FIRST :-) // marc -- // work: marc@ascend.com uunet!aria!marc // home: marc@dumbcat.sf.ca.us pacbell!dumbcat!marc
bill@bilver.uucp (Bill Vermillion) (06/26/91)
In article <243.2861EA82@zswamp.uucp> root@zswamp.uucp (Geoffrey Welsh) writes: >In a letter to All, Jonathan Hardwick (jch+@cs.cmu.edu ) wrote: > > >A housemate has an original Big Blue IBM PC, running at the blazing > >speed of 4.77MHz.... > >.... Is the PC going to be able to keep up with 19200 bps? >Answer: 9600 probably, 19200 probably not. The biggest problem is in software. Years ago, about 1984 probably, I had a terminal program called Dr. Term, from someone in the Denver area. This program had NO problems doing dumps to the PC at 19,200 with NO flow control. It was written with speed as the primary objective. The user interface was a bit weak but designed for technical users. One of the demos was to dump from a Kaypro CPM machine at full tilt into the PC. The PC can do it, given the right software. While most comm programs seem to load a buffer, and then turn off receive while writing to disk, this appeared to write continually. I suspect it wrote everytime it got enough for a new sector. When downloading to a floppy the floppy access light never went off. But on the whole, most term programs I have seen seem to stumble badly on anything approaching reasonably fast transfer speeds. -- Bill Vermillion - UUCP: ...!tarpit!bilver!bill : bill@bilver.UUCP
tnixon@hayes.uucp (06/27/91)
In article <1266@aria.ascend.com>, marc@aria.ascend.com (Marco S Hyman) writes: > A full duplex ascii transfer is _the_ comm program torture test. The > best I've found (in spite of its user interface which I hate!) is Hayes > Smartcom III. It will handle 19.2 Kbps full duplex ascii transfers on two > serial ports simultaneously. I'm glad you like the Smartcom III performance, but sorry you "hate" the user interface -- since I had a pretty significant part in designing the interface! We're always willing to listen, so if you have any ideas you'd like to share I'd be happy if you'd send me email. Same goes for everybody else, too! -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet tnixon%hayes@uunet.uu.net
root@zswamp.uucp (Geoffrey Welsh) (06/29/91)
In a letter to All, Bill Vermillion (bill@bilver.uucp ) wrote: >In article <243.2861EA82@zswamp.uucp> root@zswamp.uucp >(Geoffrey Welsh) writes: >In a letter to All, Jonathan Hardwick (jch+@cs.cmu.edu ) wrote: >> >.... Is the PC going to be able to keep up with 19200 bps? >Answer: 9600 probably, 19200 probably not. >The biggest problem is in software. I don't mean to jup on you in particular, because I've seen that response from several people and, I admit, it's 100% correct. However, it may not be all that helpful... The average user already has a favorite terminal program (perhaps he bought it, perhaps registered it as shareware), and suggesting a change of software (especially if it's not commonly available) means that the user must uproot and re-invest. On the other hand, a 16550 is never a bad investment if you do 9600+ bps async transfers on a regular basis, and comm packages that support the '550 are - I would think! - more common than those that would handle 19,200 or 38,400 on their own. Therefore I usually recommend a '550 as an inexpensive way to get the high transfer rates without spending for or re-learning a new terminal program. -- Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root 602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 "He who claims to know everything can't possibly know much" -me